Thyroid disorders are more common among women then men and hypothyroidism affects 15-20% of all women over the age of 50. If the thyroid doesn’t create or release enough thyroid hormones, it will slow down your metabolism. An underactive thyroid can thus lead to weight gain, depression, tiredness and an increased sensitivity to cold temperatures.
What is the thyroid feedback loop?
The thyroid gland is part of the hypothalamic-pituitary-thyroid axis, and the thyroid hormone secretion is exerted by what is called a negative feedback loop. Thyroid-releasing hormone (TRH) from the hypothalamus stimulates the release of Thyroid Stimulating Hormone (TSH) from the pituitary. TSH controls the production of the thyroid hormones T4 and T3 where T4 is the inactive form that is converted to the active form T3. It is the active form that is used by the thyroid gland. About a third of T4 is converted to T3 – provided we have a healthy liver, healthy gut flora and adequate nutritional levels (especially selenium and zinc). The transformation of thyroid hormones can be inhibited by factors such as heavy metals, environmental toxins, alcohol, cigarettes, inflammation, insulin resistance and certain drugs.
Which thyroid functions are tested?
This test measures free T3, free T4 and TSH. If you would like to measure thyroid antibodies, we offer another thyroid test, which measures three different types of antibodies. The presence of thyroid antibodies suggests that the cause of thyroid disease is an autoimmune disorder, such as Hashimoto’s disease or Graves’ disease. One can have normal levels of TSH, T3 and T4 and still have thyroid antibodies.
Hypothyroidism (underactive thyroid), symptoms
- Weight gain
- Being sensitive to cold
- Dry skin
- Brittle hair and nails
- Forgetfulness, brain fog
Hyperthyroidism (overactive thyroid), symptoms
- Mood swings, anxiety and irritability
- Sensitivity to heat
- Heart palpitations
- Difficulty sleeping
- Swelling in your neck from an enlarged thyroid gland (goitre)
Intake of thyroid medication or supplementing with tyrosine or phenylalanine will affect the outcome of the test.
About the test
The thyroid test is a blood test that is collected at home via capillary blood. Please note that this test requires you to fill two tubes with blood. The sample is then sent to the lab for analysis and you will receive your answer digitally as soon as the lab has analyzed your sample. Shipping to the lab is included in the price.